Re: panic: softdep_deallocate_dependencies: dangling deps

On Wednesday, September 27, 2017 03:13:21 PM Steve Kargl wrote:
> Just got this panic on 
> 
> FreeBSD troutmask.apl.washington.edu 12.0-CURRENT FreeBSD 12.0-CURRENT
> #0 r321800: Mon Jul 31 13:48:43 PDT 2017
> kargl_at_:/data/obj/usr/src/sys/SPEW  amd64
> 
> core.txt.0 contains
> 
> panic: softdep_deallocate_dependencies: dangling deps
> cpuid = 7
> time = 1506549566
> KDB: stack backtrace:
> db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe023a281710
> vpanic() at vpanic+0x19c/frame 0xfffffe023a281790
> panic() at panic+0x43/frame 0xfffffe023a2817f0
> softdep_deallocate_dependencies() at softdep_deallocate_dependencies+0x76/frame 0xfffffe023a281810
> brelse() at brelse+0x149/frame 0xfffffe023a281870
> bufwrite() at bufwrite+0x65/frame 0xfffffe023a2818b0
> softdep_process_journal() at softdep_process_journal+0x7a8/frame 0xfffffe023a281950
> softdep_process_worklist() at softdep_process_worklist+0x80/frame 0xfffffe023a2819b0
> softdep_flush() at softdep_flush+0xff/frame 0xfffffe023a2819f0
> fork_exit() at fork_exit+0x75/frame 0xfffffe023a281a30
> fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe023a281a30
> --- trap 0, rip = 0, rsp = 0, rbp = 0 ---
> 
> __curthread () at ./machine/pcpu.h:232
> 232		__asm("movq %%gs:%1,%0" : "=r" (td)
> (kgdb) #0  __curthread () at ./machine/pcpu.h:232
> #1  doadump (textdump=1) at /usr/src/sys/kern/kern_shutdown.c:318
> #2  0xffffffff805879eb in kern_reboot (howto=260)
>     at /usr/src/sys/kern/kern_shutdown.c:386
> #3  0xffffffff80587e66 in vpanic (fmt=<optimized out>, ap=0xfffffe023a2817d0)
>     at /usr/src/sys/kern/kern_shutdown.c:779
> #4  0xffffffff80587c83 in panic (fmt=<unavailable>)
>     at /usr/src/sys/kern/kern_shutdown.c:710
> #5  0xffffffff80787f56 in softdep_deallocate_dependencies (
>     bp=0xfffffe01f008d8b8) at /usr/src/sys/ufs/ffs/ffs_softdep.c:14304
> #6  0xffffffff8061dd69 in buf_deallocate (bp=0xfffffe01f008d8b8)
>     at /usr/src/sys/sys/buf.h:429
> #7  brelse (bp=0xfffffe01f008d8b8) at /usr/src/sys/kern/vfs_bio.c:2348
> #8  0xffffffff8061b9e5 in bufwrite (bp=0xfffffe01f008d8b8)
>     at /usr/src/sys/kern/vfs_bio.c:1914
> #9  0xffffffff8079bec8 in softdep_process_journal (mp=<optimized out>, 
>     needwk=0x0, flags=<optimized out>)
>     at /usr/src/sys/ufs/ffs/ffs_softdep.c:3559
> #10 0xffffffff80785dc0 in softdep_process_worklist (mp=0xfffff80007eef000, 
>     full=0) at /usr/src/sys/ufs/ffs/ffs_softdep.c:1592
> #11 0xffffffff807894ff in softdep_flush (addr=0xfffff80007eef000)
>     at /usr/src/sys/ufs/ffs/ffs_softdep.c:1397
> #12 0xffffffff80555075 in fork_exit (
>     callout=0xffffffff80789400 <softdep_flush>, arg=0xfffff80007eef000, 
>     frame=0xfffffe023a281a40) at /usr/src/sys/kern/kern_fork.c:1038
> #13 <signal handler called>
> (kgdb) 
> 
> Hmmm,
> 
> %  kgdb /usr/lib/debug/boot/kernel/kernel.debug vmcore.0
> GNU gdb (GDB) 8.0 [GDB v8.0 for FreeBSD]
> Copyright (C) 2017 Free Software Foundation, Inc.
> Type "apropos word" to search for commands related to "word"...
> Reading symbols from /usr/lib/debug/boot/kernel/kernel.debug...done.
> ABI doesn't support a vmcore target
> 
> OK, so debugging is broken :-/

Run the debugger on the binary, not the debug symbols:

kgdb /boot/kernel/kernel vmcore.0

-- 
John Baldwin